The bond offering includes a three-year, $325 million series and a five-year, $425 million series with an average interest rate of 2.6 percent — the company's lowest interest rate on a new bond offering since 2003.

The company projects that vehicle-backed interest costs will decline by $20 million to $25 million in 2012 compared to 2011 — a $5 million improvement from its projections, said David B. Wyshner, chief financial officer, in prepared remarks.